Delete the old bootloader

The new FAT32 bootloader has reached feature parity with the old bootloader (can
actually load the kernel). The new bootloader also brings some nice improvements
over the old bootloader such as loading the kernel at 1MB (fixing the potential
issue that when the kernel grows large enough it will overwrite the EBDA and
upper RAM before it ever happened) and automatically adapting to the kernel
size, and as such I believe that there is no reason to keep the old bootloader
in the source tree.